What is the EVA principle in PHP and how does it relate to separating processing from output?

The EVA principle in PHP stands for "Escape, Validate, and Aggregate". It is a best practice for separating processing from output in web applications. By following this principle, you can ensure that user input is properly sanitized, validated, and processed before being displayed to the user, which helps prevent security vulnerabilities such as cross-site scripting attacks. 

// Example of implementing the EVA principle in PHP

// Escape user input to prevent XSS attacks
$user_input = htmlspecialchars($_POST['user_input']);

// Validate user input
if (filter_var($user_input, FILTER_VALIDATE_EMAIL)) {
    // Process the input if it is a valid email address
    $processed_input = $user_input;
} else {
    // Handle invalid input
    $processed_input = "Invalid email address";
}

// Aggregate processed input for output
echo "Processed input: " . $processed_input;

Keywords

EVA principle PHP processing output separation

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